Budget cuts to key US climate programs proposed by President Donald Trump are "frightening" for the global science community, threatening to set back recent advances, a leading international researcher says.
Valerie Masson-Delmotte, co-chair of the Intergovernmental Panel on Climate Change working group, said the planned cuts were "a major worry" given America's outsized contribution to the global research.
"I cannot hide the huge anxieties about the strength of research capacities in the US in the coming years," Dr Masson-Delmotte said.
Timelapse of Arctic icebreaker with not much ice
More than a century since the first successful transit of the treacherous Northwest Passage, the impacts of climate change can be seen with the Arcticâs melting sea ice.
Geosciences, including climate research, face cuts of as much as 40 per cent, including the scrapping for four climate-related satellites. "It's a major worry given the weight of the US scientific communities" in this field, she said.
US work includes as much as 30 per cent of ocean climate research, and running core data centres used by international researchers. Such cuts, if applied, would be difficult for US universities - or other nations - to fill.
Cuts proposed by Australia's CSIRO in monitoring of the Southern Ocean stirred similar concerns last year before a public outcry prompted the Turnbull government to step in to create a special climate centre with longer-term funding guaranteed.
China has significantly increased its ocean monitoring and climate modelling work "but it is not sufficient to cover what would happen if such a big player as the US would reduce their effort", said Dr Masson-Delmotte, who is also a senior scientist at France's Laboratoire des Sciences du Climat et de l'Environnement at the Institut Pierre Simon Laplace.
While researchers continue to expand knowledge of how the rise in greenhouse gases is causing a build-up in planetary heat, important gaps remain.
Research priorities include increasing observations in remote regions, such as Antarctica, where melting ice could trigger global sea-level rises of metres over centuries if the giant sheets collapse.
More understanding is also needed about feedback processes, which could amplify climate change and trigger abrupt shifts such as in ocean circulation patterns.
A third priority is the development of models that can correctly project the changes, particularly on a regional scale.
The sixth IPCC assessment report is due to be completed in 2021, with special reports on the impacts of a 1.5-degree warming, the cryosphere, and climate change effects on land set for release in the next two years.